<template>
  <div class="app-container">
    <!--表单-->
    <el-form :inline="true" class="demo-form-inline">
      <el-form-item>
        <el-date-picker
          v-model="startDate"
          type="date"
          placeholder="选择开始日期"
          value-format="yyyy-MM-dd"
        />
      </el-form-item>
      <el-form-item>
        <el-date-picker
          v-model="endDate"
          type="date"
          placeholder="选择截止日期"
          value-format="yyyy-MM-dd"
        />
      </el-form-item>
      <el-button
        :disabled="btnDisabled"
        type="primary"
        icon="el-icon-search"
        @click="showChart()"
        >查询</el-button
      >
    </el-form>
    <div id="chart" class="chart" style="height: 500px" />
  </div>
</template>
<script>
import echarts from "echarts";
import { findCount } from "@/api/vod/videoVisitor";

export default {
  data() {
    return {
      courseId: "",
      startDate: "",
      endDate: "",
      btnDisabled: false,
    };
  },
  created() {
    this.courseId = this.$route.params.id;
    // 初始化最近十天数据
    let currentDate = new Date();
    this.startDate = this.dateFormat(
      new Date(currentDate.getTime() - 7 * 24 * 3600 * 1000)
    );
    this.endDate = this.dateFormat(currentDate);
    this.showChart();
  },
  methods: {
    showChart() {
      findCount(this.courseId, this.startDate, this.endDate).then(
        (response) => {
          this.setChartData(response.data);
        }
      );
    },
    setChartData(data) {
      // 基于准备好的dom，初始化echarts实例
      var myChart = echarts.init(document.getElementById("chart"));
      // 指定图表的配置项和数据
      var option = {
        title: {
          text: "观看课程人数统计",
        },
        xAxis: {
          data: data.xData,
        },
        yAxis: {
          minInterval: 1,
        },
        series: [
          {
            type: "line",
            data: data.yData,
          },
        ],
      };
      // 使用刚指定的配置项和数据显示图表。
      myChart.setOption(option);
    },
    dateFormat(date) {
      let fmt = "YYYY-mm-dd";
      let ret;
      const opt = {
        "Y+": date.getFullYear().toString(), // 年
        "m+": (date.getMonth() + 1).toString(), // 月
        "d+": date.getDate().toString(), // 日
        "H+": date.getHours().toString(), // 时
        "M+": date.getMinutes().toString(), // 分
        "S+": date.getSeconds().toString(), // 秒
        // 有其他格式化字符需求可以继续添加，必须转化成字符串
      };
      for (let k in opt) {
        ret = new RegExp("(" + k + ")").exec(fmt);
        if (ret) {
          fmt = fmt.replace(
            ret[1],
            ret[1].length == 1 ? opt[k] : opt[k].padStart(ret[1].length, "0")
          );
        }
      }
      return fmt;
    },
  },
};
</script>
